The present invention relates to generally surface materials, and particularly, to surface materials which are suitable for use in absorbent articles such as sanitary napkins or disposable diapers and to the absorbent articles using such surface materials.
Conventionally, nonwoven fabrics obtained through a so-called air-through process have often been used as surface materials of absorbent articles such as disposable diapers or sanitary napkins. The air-through process comprises a step of subjecting a fibrous web such as a carded web laid on an air-permeable net or a drum to hot blast so as to heat-weld component fibers at intersections thereof.
The air-through nonwoven fabrics obtained through such process are characterized by comfortably airy texture. However, on the surface of such air-through nonwoven fabrics directly exposed to hot blast (referred to hereinafter as “hot blast-exposed surface”), the component fibers are generally apt to be raised.
Taking accounting of such tendency when the air-through nonwoven fabric is used as a surface material for the absorbent article, the surface of such type of nonwoven fabric opposite to the blown surface, i.e., the surface opposed to the net or the drum (referred to hereinafter as “net-side surface”) has usually been laid so as to face the article wearer's skin.
However, a fibrous layer on the net-side surface is not apt to become airy as easily as the hot blast-exposed surface is and, in many cases, remains in a state compressed in thickness direction thereof. Therefore, if the absorbent article is designed in a manner that the fibrous layer on the net-side surface is put in contact with the wearer's skin, there will be likely that at least a portion of body fluids discharged by the article wearer might stay on and/or soak through the surface material.
Recently, there is a demand for a tangibly improved texture of the absorbent article and it has already been proposed to design the absorbent article so that the hot blast-exposed surface of the air-through nonwoven fabric is opposed to the article wearer's skin (See REFERENCE: Japanese Unexamined Patent Application Publication No. 2004-166831).
In the case of the absorbent article disclosed in this REFERENCE, a diameter of each component fibers on the hot blast-exposed surface of the air-through nonwoven fabric is dimensioned as thin as in a range of 11 to 18 μm and thereby intersections of the component fibers are increased in order to alleviate the tendency that the component fibers would readily raise on the hot blast-exposed surface. Even in this case, however, it will be impossible to restrain the raising tendency to an acceptable degree because much more component fibers on the hot blast-exposed surface than those on the net-side surface are headed in the thickness direction of the nonwoven fabric.
The conventional technique according to which the absorbent article is designed so that the net-side surface of the surface material faces the wearer's skin may result in poor absorbency for body fluids discharged by the wearer for the reason as has been described above. On the other hand, the technique disclosed in REFERENCE according to which the absorbent article is designed so that the hot blast-exposed surface of the surface material faces the wearer's skin is unable to restrain the raising tendency to an acceptable degree and consequentially to achieve touch and feeling which are comfortable for the article wearer. Therefore, there is a demand for development of the air-through nonwoven fabric improved so as to solve the problems as have been described above.